“Hi Little One. I know you, but only because I feel you. How is it possible to love someone so much already?” the Twilight star, 29, captioned her post.

“All I know for sure is it’s the strongest feeling I’ve ever felt. We’ve been sharing this body for quite some time, and we’ve already experienced so much together,” she added. “We can’t wait to meet you… Love, your parents.”

Reed recently covered Fit Pregnancy and Baby, dishing to the magazine about how she and Somerhalder, 38, have been preparing for parenthood — and the “one month of silence” they would take after their first child’s birth.

“We’ll take the baby’s first month for ourselves,” she said, posing for a stunning maternity shoot. “Just the three of us, no visitors, and we’re turning off our phones too, so there’s no expectation for us to communicate … You don’t get those first 30 days back, and we want to be fully present.”

As far as keeping their baby’s sex (“the greatest and only true surprise of your life”) a secret until delivery, Reed assured she’d be excited either way. “A close friend had a son and I remember thinking, ‘I hope I have a son one day.’ Then another friend had a girl and I thought, ‘How fun would it be to have a miniature version of yourself?’ ” she said. “You can’t lose, no matter what.”

Somerhalder opened up to PEOPLE recently about how caring for cats has helped prepare him for fatherhood. “I’ve learned to smile through cleaning endless amounts of poop and pee,” he said.

“To get up in the middle of the night to bottle feed eight kittens that would die without you, it gives you a sense of what it’s like to care for something that depends on you for its survival,” added the actor of his duties as a cat dad. “It’s a very special thing. It’s a great beginner’s course.”